test(ha-commit-engine): RED integration tests for ACK feed and sync-append (task 5.1)
Tests 30-34: wired repl_on_ack feeds engine, membership mutators
trigger re-evaluation, per-entry sync-append contract (stale-ACK
rejection, committed_lsn unmoved on timeout, n_peers=1 replaces
-ENODEV). test_repl_majority walAck cases rewired to per-LSN
semantics (configAck byte-identical). Sanctioned scaffolding:
entry_lsn param on repl_wait_majority_ack (legacy body byte-identical,
callers pass 0), inert repl_set_commit_engine stub. 9 RED failures;
baseline signatures unchanged. LSN-0 edge documented for 5.2/5.3.